Variable beam spacing, timing, and power for vehicle sensors

ABSTRACT

The present disclosure relates to systems and methods that facilitate light detection and ranging operations. An example transmit block includes at least one substrate with a plurality of angled facets. The plurality of angled facets provides a corresponding plurality of elevation angles. A set of angle differences between adjacent elevation angles includes at least two different angle difference values. A plurality of light-emitter devices is configured to emit light into an environment along the plurality of elevation angles toward respective target locations so as to provide a desired resolution and/or a respective elevation angle. The present disclosure also relates to adjusting shot power and a shot schedule based on the desired resolution and/or a respective elevation angle.

CROSS-REFERENCE TO RELATED APPLICATION

The present patent application is a non-provisional application claimingpriority to U.S. Patent Application No. 62/473,311 filed on Mar. 17,2017, the contents of which are hereby incorporated by reference.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

Vehicles can be configured to operate in an autonomous mode in which thevehicle navigates through an environment with little or no input from adriver. Such autonomous vehicles can include one or more sensors thatare configured to detect information about the environment in which thevehicle operates.

One such sensor is a light detection and ranging (LIDAR) device. A LIDARcan estimate distance to environmental features while scanning through ascene to assemble a “point cloud” indicative of reflective surfaces inthe environment. Individual points in the point cloud can be determinedby transmitting a laser pulse and detecting a returning pulse, if any,reflected from an object in the environment, and determining thedistance to the object according to the time delay between thetransmitted pulse and the reception of the reflected pulse. A laser, orset of lasers, can be rapidly and repeatedly scanned across a scene toprovide continuous real-time information on distances to reflectiveobjects in the scene. Combining the measured distances and theorientation of the laser(s) while measuring each distance allows forassociating a three-dimensional position with each returning pulse. Inthis way, a three-dimensional map of points indicative of locations ofreflective features in the environment can be generated for the entirescanning zone.

SUMMARY

The present disclosure generally relates to light-emitting systemsconfigured to provide pulses of laser light. For example, the presentdisclosure may relate to light detection and ranging (LIDAR) systemsthat may be implemented in vehicles, such as autonomous andsemi-autonomous automobiles, trucks, motorcycles, and other types ofvehicles that can move within their respective environments.

In a first aspect, a system is provided. The system includes at leastone substrate. The at least one substrate includes a plurality of angledfacets along a front edge. The at least one substrate further includes adie attach location corresponding to each angled facet. The plurality ofangled facets provides a corresponding plurality of elevation angles. Aset of angle differences between adjacent elevation angles includes atleast two different angle difference values. The system also includes aplurality of light-emitter devices. The respective light-emitter devicesare coupled to respective die attach locations according to a respectiveelevation angle of the respective angled facet. The plurality oflight-emitter devices is configured to emit light into an environmentalong the plurality of elevation angles toward respective targetlocations.

In a second aspect, a method of manufacturing is provided. The methodincludes providing at least one substrate. The at least one substrateincludes a plurality of angled facets along a front edge and a dieattach location corresponding to each angled facet. The plurality ofangled facets provides a corresponding plurality of elevation angles. Aset of angle differences between adjacent elevation angles includes atleast two different angle difference values. The method also includesattaching a plurality of light-emitter devices to respective die attachlocations. The attaching is performed according to a respectiveelevation angle of the respective angled facet. The method also includeselectrically connecting each respective light-emitter device of theplurality of light-emitter devices to a respective pulser circuit. Themethod additionally includes optically coupling each respectivelight-emitter device of the plurality of light-emitter devices to arespective lens.

In a third aspect, a method is provided. The method includes determiningan elevation angle of a given light-emitter device of a plurality oflight-emitter devices. Respective light-emitter devices are coupled torespective die attach locations corresponding to respective angledfacets of a plurality of angled facets disposed along a front edge of atleast one substrate. The method also includes determining a desiredpower output level of the given light-emitter device based on thedetermined elevation angle. The method also includes causing the givenlight-emitter device to emit at least one light pulse into anenvironment toward a target location according to the desired poweroutput level.

In a fourth aspect, a method is provided. The method includesdetermining an anticipated target range of a given light-emitter deviceof a plurality of light-emitter devices. Respective light-emitterdevices are coupled to respective die attach locations corresponding torespective angled facets of a plurality of angled facets disposed alonga front edge of at least one substrate. The method also includesdetermining a desired power output level of the given light-emitterdevice based on the determined anticipated target range. The method yetfurther includes causing the given light-emitter device to emit at leastone light pulse into an environment toward a target location accordingto the desired power output level.

In a fifth aspect, a method is provided. The method includes determininga respective elevation angle for each light-emitter device of aplurality of light-emitter devices. The respective light-emitter devicesare coupled to respective die attach locations corresponding torespective angled facets of a plurality of angled facets disposed alonga front edge of at least one substrate. The method also includesdetermining a desired shot schedule of the plurality of light-emitterdevices based on the determined elevation angles. The method yet furtherincludes causing the plurality of light-emitter devices to emit lightpulses into an environment toward a target region according to thedesired shot schedule.

In a sixth aspect, a method is provided. The method includes determiningan anticipated target range for each light-emitter device of a pluralityof light-emitter devices. Respective light-emitter devices are coupledto respective die attach locations corresponding to respective angledfacets of a plurality of angled facets disposed along a front edge of atleast one substrate. The method includes determining a desired shotschedule of the plurality of light-emitter devices based on therespective anticipated target ranges. The method also includes causingthe plurality of light-emitter devices to emit light pulses into anenvironment toward a target region according to the desired shotschedule.

In a seventh aspect, a system is provided. The system includes aplurality of light-emitter devices of a light detection and rangingsystem of a vehicle. Each light-emitter device of the plurality oflight-emitter devices is configured to emit light pulses along arespective beam elevation angle. The plurality of light-emitter devicesare arranged such that a combination of the respective beam elevationangles includes a non-uniform beam elevation angle distribution. Atleast one angle difference between respective beam elevation angles oftwo adjacent light-emitter devices having elevation angles below areference plane is larger than at least one angle difference betweenrespective beam elevation angles of two adjacent light-emitter deviceshaving elevation angles above the reference plane. The reference planeis based on an axis of motion of the vehicle.

Other aspects, embodiments, and implementations will become apparent tothose of ordinary skill in the art by reading the following detaileddescription, with reference where appropriate to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A illustrates a sensing system, according to an exampleembodiment.

FIG. 1B illustrates a transmit block, according to an exampleembodiment.

FIG. 2A illustrates a portion of a transmit block, according to anexample embodiment.

FIG. 2B illustrates a portion of a transmit block, according to anexample embodiment.

FIG. 2C illustrates a transmit block, according to an exampleembodiment.

FIG. 2D illustrates several possible beam angle distributions, accordingto an example embodiment.

FIG. 2E illustrates several possible vertical resolution plots,according to an example embodiment.

FIG. 3A illustrates a vehicle, according to an example embodiment.

FIG. 3B illustrates a vehicle in a sensing scenario, according to anexample embodiment.

FIG. 4A illustrates a portion of a transmit block, according to anexample embodiment.

FIG. 4B illustrates a portion of a transmit block, according to anexample embodiment.

FIG. 4C illustrates a portion of a transmit block, according to anexample embodiment.

FIG. 4D illustrates a close up side view of a portion of a transmitblock, according to an example embodiment.

FIG. 4E illustrates a portion of a transmit block, according to anexample embodiment.

FIG. 5 illustrates a method, according to an example embodiment.

FIG. 6A illustrates a method, according to an example embodiment.

FIG. 6B illustrates graphs, according to an example embodiment.

FIG. 7 illustrates a method, according to an example embodiment.

FIG. 8 illustrates a method, according to an example embodiment.

FIG. 9 illustrates a method, according to an example embodiment.

DETAILED DESCRIPTION

Example methods, devices, and systems are described herein. It should beunderstood that the words “example” and “exemplary” are used herein tomean “serving as an example, instance, or illustration.” Any embodimentor feature described herein as being an “example” or “exemplary” is notnecessarily to be construed as preferred or advantageous over otherembodiments or features. Other embodiments can be utilized, and otherchanges can be made, without departing from the scope of the subjectmatter presented herein.

Thus, the example embodiments described herein are not meant to belimiting.

Aspects of the present disclosure, as generally described herein, andillustrated in the figures, can be arranged, substituted, combined,separated, and designed in a wide variety of different configurations,all of which are contemplated herein.

Further, unless context suggests otherwise, the features illustrated ineach of the figures may be used in combination with one another. Thus,the figures should be generally viewed as component aspects of one ormore overall embodiments, with the understanding that not allillustrated features are necessary for each embodiment.

I. Overview

In an effort to increase imaging resolution in light detection andranging (LIDAR) systems, such systems may increase a quantity of sensingdevices and/or light-emitting devices, which may be expensive.Optionally, a shot rate of the light-emitting devices may be increased,which may increase the output power of the system and be supported byadditional cooling capabilities (e.g., heatsinks, liquid cooling, etc.).Increasing the number of shots and light pulse detections in a givenperiod of time also may need greater computational power to process.

Instead of simply increasing a number of light-emitting devices andsensing devices at evenly-spaced angle intervals to obtain betterresolution within a given field of view, example systems and methodsdescribed herein concentrate more sensing devices and/or light-emittingdevices at specific angles or ranges of angles, such as angles thatrelate to beams emitted from a transmit block of a LIDAR system thatpoint ahead of a vehicle or up, and utilize fewer sensors orlight-emitters oriented at other angles. For example, beams that pointdownward hit the ground at relatively close range. Accordingly, to seean object of a certain size (e.g., 5 cm tall or 12 cm tall), thedownward facing beams can be spaced more sparsely (in angular terms withrespect to the LIDAR system) as compared to beams that generally travellonger distances. This, in turn, provides a capability to view similarsized objects within a range of distances away from the vehicle.Additionally or alternatively, embodiments described herein may providean opportunity to reduce the number of sensing devices or light-emittingdevices. Yet further, embodiments disclosed herein may provide greaterspatial resolution for a given number of sensing devices orlight-emitting devices.

Some embodiments of the present disclosure may include varying theamount of power per shot based on an orientation of a givenlight-emitting device. That is, light-emitting devices that emitrelatively close range beams (e.g., beams emitted at downward angles)need lower power than longer range beams. Put in other words, a minimumamount of photons needed to resolve a given feature scales as a squareof the range. Accordingly, compared to an “average” shot, beams thattravel only half of the distance to their target may need only a quarterof the power per shot to detect a given object with similar accuracy. Byvarying the amount of power based on an orientation angle of a givenlight-emitting device, the LIDAR device may be more power efficient.

In conventional LIDAR systems, a shot rate may be implemented uniformlyacross all of the light-emitting devices, without regard to a maximumdetection distance. In the present disclosure, some embodiments have ashot schedule, shot rate, and/or a shot interval that may be variedbased on the orientation of a given light-emitting device or the angleof the beam to be detected. That is, as described above, light pulses indownward-oriented beams travel shorter distances and therefore thedetector may receive a corresponding reflected pulse faster than similarpulses that travel longer distances due to different times of flight.Accordingly, light-emitting devices and detectors assigned to lowerangle beams may be assigned a different duty cycle (e.g., less returnwait time) compared to higher angle beams at least because closer-rangebeams will generally provide faster return signals. Thus, after emittinga light pulse, lower angle emitter/detector pairs may have a shorterdelay or narrower window before emitting a subsequent light pulse. Thatis, adjacent lower angle emitters may fire in closer succession to oneanother as compared to higher angle emitters due, at least in part, to ashorter “listening window” during which a corresponding detector mayreceive reflected light from a given light pulse. When a given lightpulse is limited in its potential time of flight (e.g., because thelight-emitter device is angled toward the ground), such a listeningwindow may be shortened in duration. In some embodiments, by waiting ashorter amount of time between light pulses and/or before firing anadjacent light-emitter device, systems and methods described herein mayemit more light pulses in a given amount of time, which may providehigher horizontal resolution or faster whole-scene update rates.

Systems and methods described herein may include transmit blocks ofLIDAR systems that provide variable beam spacing, shot timing (e.g.,shot scheduling), and shot power, each of which may be based onvariables such as: sensor height, total number of beams, desired objectsize, minimum possible spacing between beams, range of slope changes(e.g. +3% change in grade, flat ground, −3% change in grade), minimumshot power, and shot power margin.

In some embodiments, beams may be spaced such that a desired spacingexists between beams at a given distance from the LIDAR system. Forexample, the desired spacing may be between 5 and 12 centimeters at10-50 meters from the LIDAR system on flat ground or from a surface(e.g., a front bumper) of a given vehicle supporting the LIDAR system.

In an example embodiment, beams may be spaced such that on flat ground,resolution is approximately 9.7 cm vertical spacing out to approximately25 m from the vehicle. At longer ranges, vertical spacing may increasegradually (e.g., linearly) until obtaining a particular, minimum spacing(e.g., 0.167 degrees), which may correspond to a physical limitation ofdie attach locations, light-emitter die size, and/or the substrate spaceand substrate shape. The slope of the linear increase could be set basedon a given number of emitters. In an example embodiment, the slope ofthe linear increase could be based on 50-100 emitters (e.g., 64emitters). However, more or fewer emitters are possible within the scopeof the present disclosure. Furthermore, other slopes and arrangements ofbeams are possible. In some cases, the system may be elevated from theground at heights of 1-5 meters. By spacing beams as described herein,the peak vertical resolution may be increased from 0.317 degrees to0.167 degrees and the peak horizontal resolution may be increased byabout ˜50%, from 0.180 degrees to 0.131 degrees, as compared to LIDARdevices with uniform beam angle spacing.

In other embodiments, assuming even a −15% grade change, at least 7.5 cmvertical spacing may be achieved at 25 meters for beams at lowerelevation until hitting a minimum angle spacing of 0.72 degrees. Forexample, for a 1.1 meter sensor height, a shot timing or shot schedulemay be adjusted to achieve a desired resolution at specific ranges fromthe sensor unit. For example, in some embodiments, the total number ofshots may be reduced by 35%. Furthermore, as described herein, the powerof each shot may be adjusted based on an anticipated target range and/oran elevation angle of the given light-emitter device. In an exampleembodiment, the power of each shot (or the power of each shot for agiven light-emitter device) may be adjusted to provide a 20% shot powermargin and 10% minimum power. In some embodiments, in combination withthe reduced shot count, reductions in power per shot may reduce thelaser power usage by ˜45%. It will be understood that other amounts ofreductions of power per shot are possible.

II. Example Systems

FIG. 1A illustrates a sensing system 10, according to an exampleembodiment. The sensing system 10 may be a light detection and ranging(LIDAR) system. The sensing system includes a housing 12 that houses anarrangement of various components, such as a transmit block 20, areceive block 30, a shared space 40, and a lens 50. The sensing system10 includes an arrangement of components configured to provide emittedlight beams 52 from the transmit block 20 that are collimated by thelens 50 and transmitted into an environment of the sensing system 10 ascollimated light beams 54. Furthermore, the sensing system 10 includesan arrangement of components configured to collect reflected light 56from one or more objects in the environment of the sensing system 10 bythe lens 50 for focusing towards the receive block 30 as focused light58. The reflected light 56 includes light from the collimated lightbeams 54 that was reflected by the one or more objects in theenvironment of the sensing system 10.

The emitted light beams 52 and focused light 58 may traverse the sharedspace 40 also included in the housing 10. In some embodiments, theemitted light beams 52 propagate along a transmit path through theshared space 40 and the focused light 58 propagates along a receive paththrough the shared space 40.

The sensing system 10 can determine an aspect of the one or more objects(e.g., location, shape, etc.) in the environment of the sensing system10 by processing the focused light 58 received by the receive block 30.For example, the sensing system 10 can compare a time when pulsesincluded in the emitted light beams 52 were emitted by the transmitblock 20 with a time when corresponding pulses included in the focusedlight 58 were received by the receive block 30 and determine thedistance between the one or more objects and the sensing system 10 basedon the comparison.

The housing 12 included in the sensing system 10 can provide a platformfor mounting the various components included in the sensing system 10.The housing 12 can be formed from any material capable of supporting thevarious components of the sensing system 10 included in an interiorspace of the housing 12. For example, the housing 12 may be formed froma structural material such as plastic or metal.

In some examples, the housing 12 may include optical shieldingconfigured to reduce ambient light and/or unintentional transmission ofthe emitted light beams 52 from the transmit block 20 to the receiveblock 30. The optical shielding can be provided by forming and/orcoating the outer surface of the housing 12 with a material that blocksthe ambient light from the environment. Additionally, inner surfaces ofthe housing 12 can include and/or be coated with the material describedabove to optically isolate the transmit block 20 from the receive block30 to prevent the receive block 30 from receiving the emitted lightbeams 52 before the emitted light beams 52 reach the lens 50.

In some examples, the housing 12 can be configured for electromagneticshielding to reduce electromagnetic noise (e.g., Radio Frequency (RF)Noise, etc.) from ambient environment of the sensor system 10 and/orelectromagnetic noise between the transmit block 20 and the receiveblock 30. Electromagnetic shielding can improve quality of the emittedlight beams 52 emitted by the transmit block 20 and reduce noise insignals received and/or provided by the receive block 30.Electromagnetic shielding can be achieved by forming and/or coating thehousing 12 with one or more materials such as a metal, metallic ink,metallic foam, carbon foam, or any other material configured toappropriately absorb or reflect electromagnetic radiation. Metals thatcan be used for the electromagnetic shielding can include for example,copper or nickel.

In some examples, the housing 12 can be configured to have asubstantially cylindrical shape and to rotate about an axis of thesensing system 10. For example, the housing 12 can have thesubstantially cylindrical shape with a diameter of approximately 10centimeters. In some examples, the axis is substantially vertical. Byrotating the housing 12 that includes the various components, in someexamples, a three-dimensional map of a 360 degree view of theenvironment of the sensing system 10 can be determined without frequentrecalibration of the arrangement of the various components of thesensing system 10. Additionally or alternatively, the sensing system 10can be configured to tilt the axis of rotation of the housing 12 tocontrol the field of view of the sensing system 10.

Although not illustrated in FIG. 1A, the sensing system 10 canoptionally include a mounting structure for the housing 12. The mountingstructure can include a motor or other means for rotating the housing 12about the axis of the sensing system 10. Alternatively, the mountingstructure can be included in a device and/or system other than thesensing system 10.

In some examples, the various components of the sensing system 10 suchas the transmit block 20, receive block 30, and the lens 50 can beremovably mounted to the housing 12 in predetermined positions to reduceburden of calibrating the arrangement of each component and/orsubcomponents included in each component. Thus, the housing 12 acts asthe platform for the various components of the sensing system 10 toprovide ease of assembly, maintenance, calibration, and manufacture ofthe sensing system 10.

The transmit block 20 includes a plurality of light sources 22 that canbe configured to emit the plurality of emitted light beams 52 via anexit aperture 26. In some examples, each of the plurality of emittedlight beams 52 corresponds to one of the plurality of light sources 22.The transmit block 20 can optionally include a mirror 24 along thetransmit path of the emitted light beams 52 between the light sources 22and the exit aperture 26.

The light sources 22 can include laser diodes, light emitting diodes(LED), vertical cavity surface emitting lasers (VCSEL), organic lightemitting diodes (OLED), polymer light emitting diodes (PLED), lightemitting polymers (LEP), liquid crystal displays (LCD),microelectromechanical systems (MEMS), or any other device configured toselectively transmit, reflect, and/or emit light to provide theplurality of emitted light beams 52. In some examples, the light sources22 can be configured to emit the emitted light beams 52 in a wavelengthrange that can be detected by detectors 32 included in the receive block30. The wavelength range could, for example, be in the ultraviolet,visible, and/or infrared portions of the electromagnetic spectrum. Insome examples, the wavelength range can be a narrow wavelength range,such as provided by lasers. In one example, the wavelength rangeincludes wavelengths that are approximately 905 nm. Additionally, thelight sources 22 can be configured to emit the emitted light beams 52 inthe form of pulses. In some examples, the plurality of light sources 22can be disposed on one or more substrates (e.g., printed circuit boards(PCB), flexible PCBs, etc.) and arranged to emit the plurality of lightbeams 52 towards the exit aperture 26.

In some examples, the plurality of light sources 22 can be configured toemit uncollimated light beams included in the emitted light beams 52.For example, the emitted light beams 52 can diverge in one or moredirections along the transmit path due to the uncollimated light beamsemitted by the plurality of light sources 22. In some examples, verticaland horizontal extents of the emitted light beams 52 at any positionalong the transmit path can be based on an extent of the divergence ofthe uncollimated light beams emitted by the plurality of light sources22.

The exit aperture 26 arranged along the transmit path of the emittedlight beams 52 can be configured to accommodate the vertical andhorizontal extents of the plurality of light beams 52 emitted by theplurality of light sources 22 at the exit aperture 26. It is noted thatthe block diagram shown in FIG. 1A is described in connection withfunctional modules for convenience in description. However, thefunctional modules in the block diagram of FIG. 1A can be physicallyimplemented in other locations. For example, although illustrated thatthe exit aperture 26 is included in the transmit block 20, the exitaperture 26 can be physically included in both the transmit block 20 andthe shared space 40. For example, the transmit block 20 and the sharedspace 40 can be separated by a wall that includes the exit aperture 26.In this case, the exit aperture 26 can correspond to a transparentportion of the wall. In one example, the transparent portion can be ahole or cut-away portion of the wall. In another example, the wall canbe formed from a transparent substrate (e.g., glass) coated with anon-transparent material, and the exit aperture 26 can be a portion ofthe substrate that is not coated with the non-transparent material.

In some examples of the sensing system 10, it may be desirable tominimize size of the exit aperture 26 while accommodating the verticaland horizontal extents of the plurality of light beams 52. For example,minimizing the size of the exit aperture 26 can improve the opticalshielding of the light sources 22 described above in the functions ofthe housing 12. Additionally or alternatively, the wall separating thetransmit block 20 and the shared space 40 can be arranged along thereceive path of the focused light 58, and thus, the exit aperture 26 canbe minimized to allow a larger portion of the focused light 58 to reachthe wall. For example, the wall can be coated with a reflective material(e.g., reflective surface 42 in shared space 40) and the receive pathcan include reflecting the focused light 58 by the reflective materialtowards the receive block 30. In this case, minimizing the size of theexit aperture 26 can allow a larger portion of the focused light 58 toreflect off the reflective material with which the wall is coated.

To minimize the size of the exit aperture 26, in some examples, thedivergence of the emitted light beams 52 can be reduced by partiallycollimating the uncollimated light beams emitted by the light sources 22to minimize the vertical and horizontal extents of the emitted lightbeams 52 and thus minimize the size of the exit aperture 26. Forexample, each light source of the plurality of light sources 22 caninclude a cylindrical lens arranged adjacent to the light source. Thelight source may emit a corresponding uncollimated light beam thatdiverges more in a first direction than in a second direction. Thecylindrical lens may pre-collimate the uncollimated light beam in thefirst direction to provide a partially collimated light beam, therebyreducing the divergence in the first direction. In some examples, thepartially collimated light beam diverges less in the first directionthan in the second direction. Similarly, uncollimated light beams fromother light sources of the plurality of light sources 22 can have areduced beam width in the first direction and thus the emitted lightbeams 52 can have a smaller divergence due to the partially collimatedlight beams. In this example, at least one of the vertical andhorizontal extents of the exit aperture 26 can be reduced due topartially collimating the light beams 52.

Additionally or alternatively, to minimize the size of the exit aperture26, in some examples, the light sources 22 can be arranged along ashaped surface defined by the transmit block 20. In some examples, theshaped surface may be faceted and/or substantially curved. The facetedand/or curved surface can be configured such that the emitted lightbeams 52 converge towards the exit aperture 26, and thus the verticaland horizontal extents of the emitted light beams 52 at the exitaperture 26 can be reduced due to the arrangement of the light sources22 along the faceted and/or curved surface of the transmit block 20.

In some examples, a curved surface of the transmit block 20 can includea curvature along the first direction of divergence of the emitted lightbeams 52 and a curvature along the second direction of divergence of theemitted light beams 52, such that the plurality of light beams 52converge towards a central area in front of the plurality of lightsources 22 along the transmit path.

To facilitate such curved arrangement of the light sources 22, in someexamples, the light sources 22 can be disposed on a flexible substrate(e.g., flexible PCB) having a curvature along one or more directions.For example, the curved flexible substrate can be curved along the firstdirection of divergence of the emitted light beams 52 and the seconddirection of divergence of the emitted light beams 52. Additionally oralternatively, to facilitate such curved arrangement of the lightsources 22, in some examples, the light sources 22 can be disposed on acurved edge of one or more vertically-oriented printed circuit boards(PCBs), such that the curved edge of the PCB substantially matches thecurvature of the first direction (e.g., the vertical plane of the PCB).In this example, the one or more PCBs can be mounted in the transmitblock 20 along a horizontal curvature that substantially matches thecurvature of the second direction (e.g., the horizontal plane of the oneor more PCBs). For example, the transmit block 20 can include four PCBs,with each PCB mounting sixteen light sources, so as to provide 64 lightsources along the curved surface of the transmit block 20. In thisexample, the 64 light sources are arranged in a pattern such that theemitted light beams 52 converge towards the exit aperture 26 of thetransmit block 20.

The transmit block 20 can optionally include the mirror 24 along thetransmit path of the emitted light beams 52 between the light sources 22and the exit aperture 26. By including the mirror 24 in the transmitblock 20, the transmit path of the emitted light beams 52 can be foldedto provide a smaller size of the transmit block 20 and the housing 12 ofthe sensing system 10 than a size of another transmit block where thetransmit path that is not folded.

The receive block 30 includes a plurality of detectors 32 that can beconfigured to receive the focused light 58 via an entrance aperture 36.In some examples, each of the plurality of detectors 32 is configuredand arranged to receive a portion of the focused light 58 correspondingto a light beam emitted by a corresponding light source of the pluralityof light sources 22 and reflected of the one or more objects in theenvironment of the sensing system 10. The receive block 30 canoptionally include the detectors 32 in a sealed environment having aninert gas 34.

The detectors 32 may comprise photodiodes, avalanche photodiodes,phototransistors, cameras, active pixel sensors (APS), charge coupleddevices (CCD), cryogenic detectors, or any other sensor of lightconfigured to receive focused light 58 having wavelengths in thewavelength range of the emitted light beams 52.

To facilitate receiving, by each of the detectors 32, the portion of thefocused light 58 from the corresponding light source of the plurality oflight sources 22, the detectors 32 can be disposed on one or moresubstrates and arranged accordingly. For example, the light sources 22can be arranged along a curved surface of the transmit block 20.Detectors 32 can be arranged along a curved surface of the receive block30. In some embodiments, the curved surface of the receive block 30 mayinclude a similar or identical curved surface as that of transmit block20. Thus, each of the detectors 32 may be configured to receive lightthat was originally emitted by a corresponding light source of theplurality of light sources 22.

To provide the curved surface of the receive block 30, the detectors 32can be disposed on the one or more substrates similarly to the lightsources 22 disposed in the transmit block 20. For example, the detectors32 can be disposed on a flexible substrate (e.g., flexible PCB) andarranged along the curved surface of the flexible substrate to eachreceive focused light originating from a corresponding light source ofthe light sources 22. In this example, the flexible substrate may beheld between two clamping pieces that have surfaces corresponding to theshape of the curved surface of the receive block 30. Thus, in thisexample, assembly of the receive block 30 can be simplified by slidingthe flexible substrate onto the receive block 30 and using the twoclamping pieces to hold it at the correct curvature.

The focused light 58 traversing along the receive path can be receivedby the detectors 32 via the entrance aperture 36. In some examples, theentrance aperture 36 can include a filtering window that passes lighthaving wavelengths within the wavelength range emitted by the pluralityof light sources 22 and attenuates light having other wavelengths. Inthis example, the detectors 32 receive the focused light 58substantially comprising light having the wavelengths within thewavelength range.

In some examples, the plurality of detectors 32 included in the receiveblock 30 can include, for example, avalanche photodiodes in a sealedenvironment that is filled with the inert gas 34. The inert gas 34 maycomprise, for example, nitrogen.

The shared space 40 includes the transmit path for the emitted lightbeams 52 from the transmit block 20 to the lens 50, and includes thereceive path for the focused light 58 from the lens 50 to the receiveblock 30. In some examples, the transmit path at least partiallyoverlaps with the receive path in the shared space 40. By including thetransmit path and the receive path in the shared space 40, advantageswith respect to size, cost, and/or complexity of assembly, manufacture,and/or maintenance of the sensing system 10 can be provided.

While the exit aperture 26 and the entrance aperture 36 are illustratedas being part of the transmit block 20 and the receive block 30,respectively, it is understood that such apertures may be arranged orplaced at other locations. In some embodiments, the function andstructure of the exit aperture 26 and the entrance aperture 36 may becombined. For example, the shared space 40 may include a sharedentrance/exit aperture. It will be understood that other ways to arrangethe optical components of system 10 within housing 12 are possible andcontemplated.

In some examples, the shared space 40 can include a reflective surface42. The reflective surface 42 can be arranged along the receive path andconfigured to reflect the focused light 58 towards the entrance aperture36 and onto the detectors 32. The reflective surface 42 may comprise aprism, mirror or any other optical element configured to reflect thefocused light 58 towards the entrance aperture 36 in the receive block30. In some examples, a wall may separate the shared space 40 from thetransmit block 20. In these examples, the wall may comprise atransparent substrate (e.g., glass) and the reflective surface 42 maycomprise a reflective coating on the wall with an uncoated portion forthe exit aperture 26.

In embodiments including the reflective surface 42, the reflectivesurface 42 can reduce size of the shared space 40 by folding the receivepath similarly to the mirror 24 in the transmit block 20. Additionallyor alternatively, in some examples, the reflective surface 42 can directthe focused light 58 to the receive block 30 further providingflexibility to the placement of the receive block 30 in the housing 12.For example, varying the tilt of the reflective surface 42 can cause thefocused light 58 to be reflected to various portions of the interiorspace of the housing 12, and thus the receive block 30 can be placed ina corresponding position in the housing 12. Additionally oralternatively, in this example, the sensing system 10 can be calibratedby varying the tilt of the reflective surface 42.

The lens 50 mounted to the housing 12 can have an optical power to bothcollimate the emitted light beams 52 from the light sources 22 in thetransmit block 20, and focus the reflected light 56 from the one or moreobjects in the environment of the sensing system 10 onto the detectors32 in the receive block 30. In one example, the lens 50 has a focallength of approximately 120 mm. By using the same lens 50 to performboth of these functions, instead of a transmit lens for collimating anda receive lens for focusing, advantages with respect to size, cost,and/or complexity can be provided. In some examples, collimating theemitted light beams 52 to provide the collimated light beams 54 allowsdetermining the distance travelled by the collimated light beams 54 tothe one or more objects in the environment of the sensing system 10.

While, as described herein, lens 50 is utilized as a transmit lens and areceive lens, it will be understood that separate lens and/or otheroptical elements are contemplated within the scope of the presentdisclosure. For example, lens 50 could represent distinct lenses or lenssets along discrete optical transmit and receive paths.

In an example scenario, the emitted light beams 52 from the lightsources 22 traversing along the transmit path can be collimated by thelens 50 to provide the collimated light beams 54 to the environment ofthe sensing system 10. The collimated light beams 54 may then reflectoff the one or more objects in the environment of the sensing system 10and return to the lens 50 as the reflected light 56. The lens 50 maythen collect and focus the reflected light 56 as the focused light 58onto the detectors 32 included in the receive block 30. In someexamples, aspects of the one or more objects in the environment of thesensing system 10 can be determined by comparing the emitted light beams52 with the focused light beams 58. The aspects can include, forexample, distance, shape, color, and/or material of the one or moreobjects. Additionally, in some examples, by rotating the housing 12, athree-dimensional map of the surroundings of the sensing system 10 canbe determined.

In some examples where the plurality of light sources 22 are arrangedalong a curved surface of the transmit block 20, the lens 50 can beconfigured to have a focal surface corresponding to the curved surfaceof the transmit block 20. For example, the lens 50 can include anaspheric surface outside the housing 12 and a toroidal surface insidethe housing 12 facing the shared space 40. In this example, the shape ofthe lens 50 allows the lens 50 to both collimate the emitted light beams52 and focus the reflected light 56. Additionally, in this example, theshape of the lens 50 allows the lens 50 to have the focal surfacecorresponding to the curved surface of the transmit block 20. In someexamples, the focal surface provided by the lens 50 substantiallymatches the curved shape of the transmit block 20. Additionally, in someexamples, the detectors 32 can be arranged similarly in the curved shapeof the receive block 30 to receive the focused light 58 along the curvedfocal surface provided by the lens 50. Thus, in some examples, thecurved surface of the receive block 30 may also substantially match thecurved focal surface provided by the lens 50.

FIG. 1B illustrates a transmit block 100, according to an exampleembodiment. Transmit block 100 may be similar or identical to transmitblock 20 as illustrated and described with reference to FIG. 1A.Transmit block 100 may include a light-emitter portion of LIDAR system.In some embodiments, the transmit block 100 may be incorporated as partof a sensing system of an autonomous or semi-autonomous vehicle, such asvehicle 300 as illustrated and described in reference to FIGS. 3A and3B.

In an example embodiment, transmit block 100 includes at least onesubstrate 110, a receiver 130, and a controller 150. The at least onesubstrate 110 includes a plurality of angled facets 112 along a frontedge. In some embodiments, the at least one substrate 110 may includeseveral flat circuit boards with the angled facets 112 arranged along anedge of the flat circuit boards.

The at least one substrate 110 also includes a die attach location 114corresponding to each angled facet 112. The plurality of angled facets112 provides a corresponding plurality of elevation angles. Namely, aset of angle differences between adjacent elevation angles includes atleast two different angle difference values. In other words, the angledfacets 112 are fabricated so that the corresponding elevation anglesinclude a heterogeneous set of angle differences between adjacentelevation angles. For example, while one angle difference between afirst pair of adjacent elevation angles is 0.18 degrees, another angledifference between a second pair of adjacent elevation angles could be0.3 degrees. Other angle difference values are possible and contemplatedherein. In some embodiments, some angle differences could be arbitrarilylarge (e.g., 5 degrees or more) and some angle differences may be assmall as manufacturing tolerances can provide (e.g., so as to formslightly different angles of the angled facets 112 on the substrate110).

The at least one substrate 110 includes a plurality of light-emitterdevices 116. In various embodiments, the light-emitter devices 116 mayinclude laser diodes, light-emitting diodes, or other types oflight-emitting devices. In an example embodiment, the light-emitterdevices 116 include InGaAs/GaAs laser diodes configured to emit light ata wavelength around 903 nanometers. Additionally or alternatively, thelight emitter devices 116 may include one or more master oscillatorpower amplifier (MOPA) fiber lasers. Such fiber lasers may be configuredto provide light pulses at or around 1550 nanometers and may include aseed laser and a length of active optical fiber configured to amplifythe seed laser light to higher power levels. However, other types oflight-emitting devices, materials, and emission wavelengths are possibleand contemplated.

Respective light-emitter devices 116 are coupled to respective dieattach locations 114 according to a respective elevation angle of therespective angled facet 112. The plurality of light-emitter devices 116is configured to emit light into an environment along the plurality ofelevation angles toward respective target locations so as to provide adesired resolution.

In some embodiments, the desired resolution could include a targetresolution at a given distance away from the transmit block 100. Forexample, the desired resolution may include a resolution of 7.5centimeters at 25 meters from the transmit block 100 and/or betweenadjacent target locations along a horizontal ground plane, whichever iscloser. Other desired resolutions, both along a two-dimensional surfaceand within three-dimensional space, are possible and contemplatedherein.

In some embodiments, the at least one substrate 110 may be disposedalong a vertical plane. In such a scenario, the plurality of elevationangles may be defined with respect to a horizontal plane. As an example,one or more of the substrates 110 may be oriented vertically within ahousing configured to spin about a vertical axis.

In such a scenario, at least one respective angle difference betweenadjacent elevation angles below the horizontal plane may be greater thanrespective angle differences between adjacent elevation angles above thehorizontal plane.

As an example, transmit block 100 may include six substrates. Eachsubstrate includes a respective plurality of angled facets thatcorrespond to a respective portion of the plurality of elevation angles.In some embodiments, the plurality of elevation angles may include anon-overlapping set of angles by which light is emitted into theenvironment about transmit block 100.

In some embodiments, the six substrates may be coupled together andaligned according to a set of alignment features 124. The set ofalignment features 124 may include a set of slots, grooves, or otherphysical features configured to reliably align the substrates 110 withrespect to one another and/or the housing.

The plurality of light-emitter devices 116 may be distributed betweeneach of the substrates 110. Each portion of the plurality oflight-emitter devices 116 is configured to illuminate the environment ata respective pointing angle with respect to the vertical plane. As anexample, the plurality of light-emitter devices 116 may include at least64 light-emitter devices. However, a greater or fewer number oflight-emitter devices 116 could be used.

In some embodiments, the at least one substrate 110 may also include,for each light-emitter device 116, a respective pulser circuit 120. Eachrespective pulser circuit 120 is configured to accept one or moresignals, such as a power signal, an enable signal, and a trigger signalvia a communication interface 122. The respective pulser circuits 120are configured to provide light pulses between approximately 1-10nanoseconds in duration. Other light pulse durations are possible.

In some embodiments, transmit block 100 may include optical elements118, which could include respective lenses optically coupled to arespective output facet of the respective light-emitter devices 116. Therespective lenses may include, but are not limited to, fast-axiscollimating lenses.

The receiver 130 may include a device configured to receive at least aportion of the light emitted from the light-emitter devices 116 so as tocorrelate a received light pulse with an object in the environment oftransmit block 100. The receiver 130 may include a plurality of lightdetection devices (e.g., InGaAs photodetectors). In some embodiments,the light detection devices may include single photon avalanchephotodetectors (SPADs). Other types of photodetectors are possible andcontemplated.

The controller 150 may include an on-board computer, an externalcomputer, or a mobile computing platform, such as a smartphone, tabletdevice, personal computer, wearable device, etc. Additionally oralternatively, the controller 150 may include, or be connected to, aremotely-located computer system, such as a cloud server. In an exampleembodiment, the controller 150 may be configured to carry out some orall method blocks or steps described herein.

The controller 150 may include one or more processors 152 and at leastone memory 154. The processor 152 may include, for instance, anapplication-specific integrated circuit (ASIC) or a field-programmablegate array (FPGA). Other types of processors, computers, or devicesconfigured to carry out software instructions are contemplated herein.The memory 154 may include a non-transitory computer-readable medium,such as, but not limited to, read-only memory (ROM), programmableread-only memory (PROM), erasable programmable read-only memory (EPROM),electrically erasable programmable read-only memory (EEPROM),non-volatile random-access memory (e.g., flash memory), a solid statedrive (SSD), a hard disk drive (HDD), a Compact Disc (CD), a DigitalVideo Disk (DVD), a digital tape, read/write (R/W) CDs, R/W DVDs, etc.

FIGS. 2A-2C illustrate various views of transmit blocks 200 and 260.FIGS. 2A-2C may include elements that are similar or identical totransmit blocks 20 and 100 illustrated and described in reference toFIGS. 1A and 1B. FIG. 2A illustrates a portion of transmit block 200,according to an example embodiment. Transmit block 200 includes asubstrate 210, which may include a printed circuit board or another typeof rigid support member. The substrate 210 may be oriented along avertical plane (e.g., the x-z plane), and/or along a plane that isperpendicular to a ground surface upon which a vehicle may travel.

At least one edge surface 202 of the substrate 210 may be formed, cut,or otherwise shaped to include a plurality of angled facets 212 a-212 j.The angled facets 212 a-212 j may be provided along the edge surface 202of the substrate 210.

Each angled facet 212 a-212 j may provide a respective elevation angle213 a-213 j with respect to a reference angle 204. The reference angle204 could, for example, correspond to a horizontal plane (e.g., the x-yplane). Some angled facets may provide negative elevation angles, thatis, elevation angles below the reference angle 204. For example, angledfacet 212 a may provide an elevation angle 215 a that is declined withrespect to the reference angle 204. Other angled facets may providepositive elevation angles or elevation angles above the reference angle204. As an example, angled facet 212 j may provide an elevation angle215 j that is inclined with respect to the reference angle 204.

As described elsewhere herein, at least one respective angle differencebetween adjacent elevation angles below the reference angle 204 (e.g.,the angle difference between elevation angles 213 a and 213 b) isgreater than respective angle differences between adjacent elevationangles above the reference angle 204 (e.g., the angle difference betweenelevation angles 213 h and 213 j). In other words, with the referenceangle 204 corresponding to the horizontal plane, the angle differencebetween adjacent downward-pointing elevation angles may be larger thanadjacent upward-pointing elevation angles.

As illustrated herein, the reference angle 204 may correspond with anx-axis, which may in turn be horizontal and/or parallel to an axis ofmotion of a vehicle. In some embodiments, the elevation angles 213 a-213j may include a range of angles between approximately −18 degrees and+2.5 degrees with respect to the reference angle 204. However, otherelevation angles (and ranges of angles) are possible and contemplatedherein.

Although not illustrated herein, some embodiments may include theelevation angles 213 a-213 j as being based on a reference plane. Thereference plane could be, for example, a horizontal plane (e.g., a planeparallel to the ground), a vertical plane (e.g., a plane perpendicularto the ground), or another plane defined by a direction of motion of theLIDAR system and/or motion of the vehicle to which the LIDAR system isattached.

As illustrated in FIG. 2A, a portion of the substrate 210 adjacent toeach angled facet 212 a-212 j includes respective die attach locations214 a-214 j.

FIG. 2B illustrates a portion of transmit block 200, according to anexample embodiment. As illustrated in the close-up side view, a lightemitter device (e.g., light emitter device 216 c) may be coupled at eachdie attach location (e.g., die attach location 214 c). Furthermore, theemitting surface 217 c of the light emitter device 216 c may be adjacentto, and/or aligned to, the angled facet 212 c. In some embodiments, anoptical element 218 c may be positioned, coupled, and/or mountedadjacent to the emitting surface 217 c of the light emitter device 216c. In an example embodiment, the optical element 218 c may include alens or another type of optical device configured to focus, steer,collimate, or otherwise interact with the light emitted from theemitting surface 217 c of the light emitter device 216 c.

In an example embodiment, transmit block 200 may include a plurality ofpulser circuits (e.g., pulser circuit 220 c). The pulser circuits may beconfigured to provide trigger pulses to the plurality of light emitterdevices. Furthermore, while FIG. 2B illustrates a respective pulsercircuit (e.g., 220 c) for each light emitter device, it will beunderstood that a single centralized pulser circuit may be providedadditionally or alternatively. Furthermore, instead of individual lenselements, it will be understood that a single lens could be used toaffect the light emitted from the emitting surface of the light emitterdevices. It will also be understood that the close-up side viewillustrates elements of transmit block 200 that may be repeated orduplicated for each die attach location 214 a-214 j and/or angled facet212 a-212 j.

Transmit block 200 includes a socket 221. The socket 221 may include anelectrical coupling to a main controller and/or other substrates intransmit block 200. For example, the other substrates in transmit block200 may include respective sets of light emitter devices, each of whichmay be oriented at a slightly different angle with respect to thehorizontal plane.

Transmit block 200 includes a communication interface 222. Thecommunication interface 222 may include one or more integrated circuitsconfigured to provide wired or wireless connectivity to other componentsof transmit block 200.

Transmit block 200 also includes various electronic components 223 a and223 b, which may include a power supply, processors, logic units, orother types of computer components.

Transmit block 200 includes alignment features 224. The alignmentfeatures 224 could include holes, slots, grooves, edges, or another typeof physical structure configured to provide reliable fiducial alignmentand/or registration between a plurality of substrates 210 in the system200. In an example embodiment, one or more fiducial pins and/orstandoffs may pass through holes in six respective substrates 210 of thetransmit block 200 so as to align the substrates 210 with respect to oneanother.

FIG. 2C illustrates a top cross-sectional view of a transmit block 260,according to an example embodiment. Transmit block 260 includes sixsubstrates 210 a-210 f. Each of the substrates 210 a-210 f includerespective pluralities of light emitter devices 261 a-f. Furthermore, insome embodiments, the light emitted from the respective pluralities oflight emitter devices 216 a-f may be oriented at respective pointingangles 264 a-264 f with regard to respective reference axes 266 a-266 fThat is, light emitter devices 261 a on substrate 210 a may be orientedto emit light at a first pointing angle 264 a with respect to an axisparallel to the x-z plane (e.g., reference axis 266 a). Light emitterdevices 261 b on substrate 210 b may be oriented to emit light at asecond pointing angle 264 b with respect to an axis parallel to the x-zplane (e.g., reference axis 266 b), and so on for the other substrates210 c-210 f. In some embodiments, the pointing angle for each substrateand/or individual light emitter device may be provided by adjusting aposition of an optical element (e.g., optical element 218 c) withrespect to the emitting surface of the respective light emitter device.In other embodiments, the pointing angle may be provided by physicallyarranging the respective substrates so that they are not parallel withrespect to one another. In some embodiments, pointing angles could rangefrom approximately −5 degrees to +5 degrees. However other pointingangle ranges are possible and contemplated in the present disclosure.

FIG. 2D illustrates several possible beam angle distributions 270 for anarbitrary number of light emitter devices, according to an exampleembodiment. For example, beam angle distributions 274 and 276 representnon-uniform angle distributions over a set of beam angles betweenroughly −18 degrees and +2 degrees. In such distributions, based on thenon-linear shape of the beam angle distributions 274 and 276, feweremitters and their respective beam angles are pointed downward (negativebeam elevation angles) in comparison to the uniform, linear beam angledistribution 272. While two different non-uniform beam angledistributions are illustrated, it will be understood that otherdistributions are possible and contemplated herein. For example,non-linear beam angle distributions between roughly −10 degrees to +10degrees are also considered herein.

FIG. 2E illustrates several possible vertical resolution plots 280,according to an example embodiment. The respective vertical resolutionplots 282, 284, and 286 illustrate different design resolutions atvarious distances from a front portion of a vehicle (e.g., the frontbumper of vehicle 300 as illustrated and described with regard to FIGS.3A and 3B). Such design resolutions may serve as a basis for a desiredbeam angle distribution, such as those illustrated and described in FIG.2D.

In an example embodiment, a linearly-increasing vertical resolution withrespect to the distance from the front bumper (e.g., vertical resolutionplot 286) may be provided by a plurality of light-emitter devices with auniform beam angle distribution. In an example embodiment, verticalresolution plot 286 illustrates a vertical resolution that increaseslinearly with distance from a resolution of 0.03 meters at the frontbumper to an approximate resolution of 0.42 meters at a distance of 75meters from the front bumper.

In contrast, a non-linear vertical resolution may be provided by aplurality of light-emitter devices arranged with a non-uniform beamangle distribution, such as those described herein. Specifically,vertical resolution plot 284 includes a vertical resolution ofapproximately 0.09 meters (measured between adjacent light beams) fromthe front bumper out to 25 meters, at which point the verticalresolution may increase linearly with distance to a maximum spacing ofapproximately 0.28 meters between adjacent beams at 90 meters from thefront bumper. As a further example, vertical resolution plot 282includes a vertical resolution of approximately 0.1 meters from thefront bumper out to 30 meters, at which point the vertical resolutionmay increase linearly with distance to a maximum of approximately 0.26meters between adjacent beams at 90 meters from the front bumper. Itwill be understood that other non-linear vertical resolutions arepossible and contemplated herein.

FIG. 3A illustrates a vehicle 300, according to an example embodiment.The vehicle 300 may include one or more sensor systems 302, 304, 306,308, and 310. The one or more sensor systems 302, 304, 306, 308, and 310could be similar or identical to sensor system 10. As an example, sensorsystems 302, 304, 306, 308, and 310 may include transmit blocks 20, 200,and 260 as illustrated and described with reference to FIGS. 1A, 2A, 2B,and 2C. Namely, sensor systems 302, 304, 306, 308, and 310 could includeLIDAR sensors having a plurality of light-emitter devices arranged overa range of angles with respect to a given plane (e.g., the x-y plane).One or more of the sensor systems 302, 304, 306, 308, and 310 may beconfigured to rotate about an axis (e.g., the z-axis) perpendicular tothe given plane so as to illuminate an environment around the vehicle300 with light pulses. Based on detecting various aspects of reflectedlight pulses (e.g., the elapsed time of flight, polarization, etc.),information about the environment may be determined.

In an example embodiment, sensor systems 302, 304, 306, 308, and 310 maybe configured to provide respective point cloud information that mayrelate to physical objects within the environment of the vehicle 300.

FIG. 3B illustrates a vehicle 300 in a sensing scenario 320, accordingto an example embodiment. In such a scenario, sensor system 302 may beconfigured to emit light pulses into an environment of the vehicle 300over an angle range 330 between a maximum angle 328 and a minimum angle330. The angle range 330 may include a downward-pointing range 334(e.g., angles below a horizontal plane 322) and an upward-pointing range332 (e.g., angles above the horizontal plane 322). In some embodiments,a plurality of light-emitter devices of sensor system 302 may be arearranged in a non-linear angle distribution over the downward-pointingangle range 334. That is, to achieve a desired vertical beam resolution,the plurality of light-emitter devices of sensor system 302 may bearranged over beam elevations that include heterogeneous elevation angledifferences between adjacent beams similar to those illustrated anddescribed with regards to FIGS. 2D and 2E.

As a further example, sensor system 304 may be configured to emit lightpulses into an environment of the vehicle 300 over an angle range 340,which may be defined between a maximum angle 360 and a minimum angle362. The angle range 340 may include a downward-pointing range 344(e.g., angles below a horizontal plane 324) and an upward-pointing range342 (e.g., angles above the horizontal plane 324). In some embodiments,a plurality of light-emitter devices of sensor system 304 may illuminatethe environment about the vehicle 300 with a non-linear angledistribution. That is, to achieve a desired vertical beam resolution,the plurality of light-emitter devices of sensor system 304 may bearranged over a set of beam elevations that include heterogeneousdifferences in elevation angle between adjacent beams similar to thoseillustrated and described with regards to FIGS. 2D and 2E.

By arranging the light-emitter devices of the respective sensor systems302 and 304, a more uniform vertical beam resolution may be provided.Such vertical beam scanning resolutions may allow more reliable and/ormore accurate sensing of various objects 350 and 352 as well as trafficsignals 354 in the environment of the vehicle 300.

While systems 10, 100, 200, 260, and sensor systems 302, 304, 306, 308,and 310 and 320 are illustrated as including certain features, it willbe understood that other types of systems are contemplated within thescope of the present disclosure.

As an example, an example embodiment may include a system having aplurality of light-emitter devices. The system may include a transmitblock of a LIDAR device. For example, the system may be, or may be partof, a LIDAR device of a vehicle (e.g., a car, a truck, a motorcycle, agolf cart, an aerial vehicle, a boat, etc.). Each light-emitter deviceof the plurality of light-emitter devices is configured to emit lightpulses along a respective beam elevation angle. The respective beamelevation angles could be based on a reference angle or reference plane,as described elsewhere herein. In some embodiments, the reference planeis based on an axis of motion of the vehicle.

The plurality of light-emitter devices in this example embodiment arearranged such that a combination of the respective beam elevation anglesincludes a non-uniform beam elevation angle distribution. That is, therespective angle differences between adjacent light-emitter devices mayvary from neighbor-to-neighbor. In an example embodiment, at least oneangle difference between respective beam elevation angles of twoadjacent light-emitter devices having elevation angles below a referenceplane is larger than at least one angle difference between respectivebeam elevation angles of two adjacent light-emitter devices havingelevation angles above the reference plane. In other words, the angledifference between two adjacent downward-pointing light-emitter devicesmay be larger than the angle difference between two adjacentupward-pointing light-emitter devices.

Optionally, in some embodiments, less than 50% of the plurality oflight-emitter devices are associated with beam elevation angles belowthe reference plane.

Additionally or alternatively, at least one light-emitter device with arespective elevation angle below the reference plane is configured toemit light pulses with a different shot schedule than at least onelight-emitter device with a respective elevation angle above thereference plane.

In some embodiments, at least one light-emitter device with a respectiveelevation angle above the reference plane may be configured to emitlight pulses with a lower duty cycle than at least one light-emitterdevice with a respective elevation angle below the reference plane.

In yet further embodiments, at least one light-emitter device with arespective elevation angle below the reference plane is configured toemit light pulses with a lower duty cycle than at least onelight-emitter device with a respective elevation angle above thereference plane.

In some cases, at least one light-emitter device with a respectiveelevation angle below the reference plane is configured to emit lightpulses with a lower power output per pulse than at least onelight-emitter device with a respective elevation angle above thereference plane.

While certain description and illustrations herein describe systems withmultiple light-emitter devices, LIDAR systems with few light-emitterdevices (e.g., a single light-emitter device) are also contemplatedherein. For example, light pulses emitted by a laser diode may bescanned about an environment of the system. The angle of emission of thelight pulses may be adjusted by a scanning device such as, for instance,a mechanical scanning mirror and/or a rotational motor. For example, thescanning devices could rotate in a reciprocating motion about a givenaxis and/or rotate about a vertical axis. In another embodiment, thelight-emitter device may emit light pulses towards a spinning prismmirror, which may cause the light pulses to be emitted into theenvironment based on an angle of the prism mirror angle when interactingwith each light pulse. Additionally or alternatively, scanning opticsand/or other types of electro-opto-mechanical devices are possible toscan the light pulses about the environment.

In some embodiments, a single light-emitter device may emit light pulsesaccording to a variable shot schedule and/or with variable power pershot, as described herein. That is, emission power and/or timing of eachlaser pulse or shot may be based on a respective elevation angle of theshot. Furthermore, the variable shot schedule could be based onproviding a desired vertical spacing at a given distance from the LIDARsystem or from a surface (e.g., a front bumper) of a given vehiclesupporting the LIDAR system. As an example, when the light pulses fromthe light-emitter device are directed downwards, the power-per-shotcould be decreased due to a shorter anticipated maximum distance totarget. Conversely, light pulses emitted by the light-emitter device atan elevation angle above a reference plane may have a relatively higherpower-per-shot so as to provide sufficient signal-to-noise to adequatelydetect pulses that travel longer distances.

Furthermore, the shot schedule could be adjusted to reduce the wait timeuntil a subsequent shot for a light pulse that is directed downwards.That is, due to a shorter distance traveled, the listening window maynot be as long in duration as that for light pulses that travel fartherwithin a given environment.

III. Example Methods

FIGS. 4A-4E illustrate various portion of a transmit block formed as amethod 500 (illustrated in FIG. 5) for manufacturing an optical system400 is carried out. FIGS. 4A-4E and 5 may include elements that aresimilar or identical to those illustrated and described with referenceto FIGS. 1A, 1B, 2A, 2B, 2C, 3A, and/or 3B. It will be understood thatthe method of manufacturing 500 may include fewer or more steps orblocks of method 500 than those expressly disclosed herein. Furthermore,respective steps or blocks of method 500 may be performed in any orderand each step or block may be performed one or more times. In someembodiments, method 500 may be combined with one or more of methods 600,700, 800, or 900.

Block 502 of method 500 includes providing at least one substrate. Theat least one substrate includes a plurality of angled facets along afront edge and a die attach location corresponding to each angled facet.The plurality of angled facets provides a corresponding plurality ofelevation angles. In such a scenario, a set of angle differences betweenadjacent elevation angles includes at least two different angledifference values.

FIG. 4A illustrates a portion of a transmit block 400 that includes asubstrate 410. Substrate 410 may be formed from a printed circuit boardmaterial. In some embodiments, the substrate 410 may be formed by lasercutting and precision drilling operations. The substrate 410 may includea wire bondable finish, such as Electroless Nickel-ElectrolessPalladium-Immersion Gold (ENEPIG). The at least one substrate 410includes a plurality of angled facets 412 a-412 j along a front edge anda die attach location (e.g., die attach locations 414 a-414 j)corresponding to each angled facet 412 a-412 j. In such a scenario, theplurality of angled facets 412 a-412 j provides a correspondingplurality of elevation angles. In an example embodiment, a set of angledifferences between adjacent elevation angles may include at least twodifferent angle difference values. That is, the elevation angles do notinclude a uniform angle difference, but rather the angle differences maydiffer from one another based on, for example, the respective elevationangles and whether the elevation angles are oriented below or above ahorizontal plane. Generally, elevation angles oriented below thehorizontal may be more widely spaced for at least the reason that thephotons are unlikely to travel as far as those at higher elevationangles. As such, to achieve a given resolution of an environment aroundthe optical system 400, fewer downward-pointing light beams can beprovided in comparison to those with forward- or upward-pointing lightbeams.

Block 504 of method 500 includes attaching a plurality of light-emitterdevices to respective die attach locations. In such a scenario, theattaching is performed according to a respective elevation angle of therespective angled facet.

FIG. 4B illustrates a portion of a transmit block 400 followingattachment of a plurality of light-emitter devices 416 a-416 j torespective die attach locations 414 a-414 j. In such a scenario, theattaching may be performed according to a respective elevation angle ofthe respective angled facet 412 a-412 j.

Block 506 of method 500 includes electrically connecting each respectivelight-emitter device of the plurality of light-emitter devices to arespective pulser circuit.

FIGS. 4C and 4D illustrate a portion of the transmit block 400 afterelectrically-connecting respective light-emitter devices 416 a-416 j torespective pulser circuits 420 a-420 j. For example, as illustrated inFIG. 4D, wire bonds 442 may be used to electrically connect thelight-emitter device 416 c to the pulser circuit 420 c. In suchscenarios, electrically-connecting the respective light-emitter devicesto the respective pulser circuits may include providing a plurality ofwire bonds (e.g., four 25 micron diameter wire bonds) between therespective light-emitter device and the respective pulser circuit. Otherways to electrically connect the light-emitter device 416 c to thepulser circuit 420 c are contemplated. For example, such electricalconnections could be fabricated as part of an integrated pulser circuitthat is hybridized (e.g., via indium bump bonds, wafer bonding, or otherflip-chip methods) to the light-emitter device.

Block 508 includes optically aligning, such as by coupling eachrespective light-emitter device of the plurality of light-emitterdevices to a respective lens.

As illustrated in the close-up side view 440, a lens 418 c may becoupled to a light-emitter device 416 c. In such a scenario, the lens418 c may be aligned with the light-emitter device 416 c so that light446 emitted from the light-emitter device 416 c impinges on, orotherwise interacts with, a desired target location 444. As an example,aligning the respective lenses to the respective light-emitter devices(e.g., light-emitter device 416 c) may include an active opticalfeedback control process. The active optical feedback control processmay include causing the respective light-emitter device 416 c to emitlight 446 and then adjusting a position of the respective lens 418 csuch that a target location 444 is illuminated by the emitted light 446.

In some embodiments, method 500 may include attaching the respectivelenses to their respective light-emitter devices. That is, in referenceto FIG. 4D, once aligned, the lens 418 c may be fixed (e.g., by gluing,clamping, or another attachment method) in place with respect to thelight-emitter device 416 c. In an example embodiment, attaching theplurality of light-emitting devices could be performed with aconductive, thermally-cured adhesive.

FIG. 4E illustrates further portions of method 500, according to anexample embodiment. Namely, the method 500 may include attaching,assembling, or otherwise providing additional elements, such asalignment features 424, communication interface 422, socket 421, andother electronic components 423 a and 423 b.

In some embodiments, method 500 may include aligning a plurality ofsubstrates 410 to one another. For example, the plurality of substratesmay be aligned by way of the alignment features 424 and/or with anycombination of alignment pins, standoffs, fiducials, or other structuresconfigured to reliably align the substrates with respect to one anotherand maintain such alignment during operation of optical system 400. Insuch a scenario, each of the substrates may include respectivepluralities of angled facets, which in combination may provide aplurality of unique elevation angles over a non-linear angledistribution as described herein.

FIG. 6A illustrates a method 600, according to an example embodiment.Method 600 may provide a way to adjust a power level of a given lightpulse or pulse train emitted by a given light-emitter device based on arespective elevation angle of the light-emitter device. Method 600 mayinvolve elements that are similar or identical to those illustrated anddescribed in reference to FIGS. 1A, 1B, 2A, 2B, 2C, 3A, and/or 3B. Itwill be understood that the method 600 may include fewer or more stepsor blocks than those expressly described herein. Furthermore, respectivesteps or blocks of method 600 may be performed in any order and eachstep or block of method 600 may be performed one or more times. In someembodiments, method 600 may be combined with one or more of methods 500,700, 800, or 900.

Block 602 includes determining an elevation angle of a givenlight-emitter device of a plurality of light-emitter devices. In such ascenario, the respective light-emitter devices are coupled to respectivedie attach locations corresponding to respective angled facets of aplurality of angled facets disposed along a front edge of at least onesubstrate. In some embodiments, determining the elevation angle of thegiven light-emitter device may be based on an arrangement of therespective light-emitter device on the at least one substrate, asdescribed elsewhere herein.

Block 604 includes determining a desired power output level of the givenlight-emitter device based on the determined elevation angle. In someembodiments, the desired power output level could be increased ordecreased from a standard power output level based on the determinedelevation angle. In some embodiments, the standard power output levelcould include a default power per shot that the LIDAR may provide forshots with an elevation angle above a reference plane (e.g., thehorizontal plane). In such scenarios, the elevation angle may limit adistance that a given light pulse may travel before it interacts with aground surface or a physical object. For example, the desired poweroutput level may be decreased in cases where, for example, the elevationangle is below the horizontal plane (zero degrees) or below −5 degreesfrom the horizontal. In other scenarios, the desired power output levelmay be increased when the determined elevation angle is above, forexample, −5 degrees or the horizontal plane (zero degrees).

In some example embodiments, determining the desired power output levelmay be further based on a comparison between the determined elevationangle and at least one value in a lookup table. In some instances, thelookup table may be stored in memory 154 and may be updated dynamicallybased on, for example, real-time or historic point cloud data.

Optional Block 606 includes causing the given light-emitter device toemit at least one light pulse into an environment toward a targetlocation according to the desired power output level. For example, apulser circuit may cause a laser diode to emit a light pulse or aplurality of light pulses (e.g., a pulse train). In such a scenario,each light pulse may be emitted at a power level that is based on theelevation angle of the emitted light. In some embodiments, light pulseswith elevation angles below a reference plane (e.g., the horizontalplane) may be emitted with lower power than light pulses with elevationangles above the reference plane.

In some embodiments, method 600 may include determining a region ofinterest in the environment. In such scenarios, determining the desiredpower output level is further based on determining that the region ofinterest corresponds to the target location of the given light-emitterdevice. For example, if a region of interest is determined, the poweroutput level of a given light pulse of a light-emitter device with atarget location that corresponds to the region of interest may beadjusted to be greater or less than a normal value.

A region of interest may relate to a possible object within theenvironment of an autonomous vehicle, such as vehicle 300 as illustratedand described with reference to FIG. 3B.

In some embodiments, method 600 may also include receiving informationindicative of a reference angle. In such cases, determining theelevation angle may be based on the received information. The referenceangle could relate to, for example, a forward movement direction of thevehicle 300. For instance, the forward movement direction of the vehicle300 may change as the vehicle moves along a hilly road. In such ascenario, more power may be applied to at least some laser pulses thatare emitted at a higher effective elevation angle (e.g., due to thevehicle going up a hill) at least because the laser pulse may travel alonger distance (and be subject to more scattering and otherinterference effects) compared to if the vehicle was traveling along aflat surface. Conversely, in some situations, less power may be appliedto at least some laser pulses, which may be emitted at a lower effectiveelevation angle (e.g., due to the vehicle moving down a hill). In suchscenarios, the laser pulses may travel a shorter distance beforeinteracting with an object, and may thus operate acceptably with lesspower than in a flat-surface scenario.

FIG. 6B illustrates graphs 620 and 630, according to an exampleembodiment. Graph 620 illustrates a maximum possible shot range inmeters versus beam elevation angle in degrees for a LIDAR system at agiven height (e.g., 2 meters). For example, for a beam pitch of −88.5degrees, that is, a beam that is pointed almost directly downwards mayhave a maximum possible shot range of 0.98 meters. That is, light pulsesemitted by a light-emitter device angled downward at −88.5 degrees wouldnormally interact with the ground after traveling 0.98 meters at themost, assuming the vehicle and LIDAR system is tilted less than athreshold angle from the ground surface. In such a scenario, the roundtrip of a reflected portion of the light pulses may be approximately 2meters. Of course, the light pulses may interact with an object locatedabove the ground surface, which would result in a shorter return trip.In either case, the short round trip distance of the light pulses mayallow the use of relatively little power at least because of a shorterinteraction distance with light attenuating/scattering media (e.g., air,dust, etc.).

Accordingly, as illustrated by graph 630, the power provided to thegiven light-emitter to provide a given signal to noise ratio may be muchless (e.g., 6.7% standard power) than that of, for example, alight-emitter device with a beam pitch of −10 degrees (100% standardpower). As such, the downward angle of the beam pitch provides a maximumthreshold distance at the ground surface boundary. Based on this maximumdistance, the power can be decreased to maintain reliable objectdetection without wasting excess power.

It will be understood that graphs 620 and 630 illustrate an exampleembodiment and that many other variations are possible. For example, theindividual beam pitches may vary, as well as the angular range of beampitches. Furthermore, the power fraction assigned to a given beam pitchmay vary based on, without limitation, surrounding topography, objectsin the environment, a mounting height of the sensor unit, a speed and/ordirection of motion of the vehicle, a background light level, anemission wavelength, a charge level of a battery that provides thelight-emitter devices with power, an operational age of the respectivelight-emitter devices, among other considerations.

FIG. 7 illustrates a method 700, according to an example embodiment.Method 700 may provide a way to adjust a power level of a given lightpulse or pulse train emitted by a given light-emitter device based on ananticipated target range. Method 700 may involve elements that aresimilar or identical to those illustrated and described in reference toFIGS. 1A, 1B, 2A, 2B, 2C, 3A, and/or 3B. It will be understood that themethod 700 may include fewer or more steps or blocks than thoseexpressly disclosed herein. Furthermore, respective steps or blocks ofmethod 700 may be performed in any order and each step or block ofmethod 700 may be performed one or more times. In some embodiments,method 700 may be combined with one or more of methods 500, 600, 800, or900.

Block 702 includes determining an anticipated target range of a givenlight-emitter device of a plurality of light-emitter devices. Therespective light-emitter devices are coupled to respective die attachlocations corresponding to respective angled facets of a plurality ofangled facets disposed along a front edge of at least one substrate. Theanticipated target range could be based, at least in part, on therespective arrangements of light-emitter devices on the at least onesubstrate. The anticipated target range could be additionally oralternatively based on a ground surface. In other embodiments, theanticipated target range could be additionally or alternatively based onhistorical point cloud data and/or target object recognitioninformation. That is, an anticipated target range may relate to apreviously-scanned, and/or specifically identified, target object. Inother words, the anticipated target range could be based on informationobtained from an earlier scan by the LIDAR device, another LIDAR deviceor another vehicle at an earlier time.

Block 704 includes determining a desired power output level of the givenlight-emitter device based on the determined anticipated target range.In some embodiments, determining the desired power output level may befurther based on a comparison between the anticipated target range andat least one value in a lookup table, which could be similar oridentical to table 620 as illustrated and described with regard to FIG.6B. In some instances, the lookup table may be stored in memory 154 andmay be updated dynamically based on, for example, real-time or historicpoint cloud data. For instance, real-time point cloud data during afirst LIDAR scan may provide locations of physical objects with theenvironment of the vehicle. Some or all of the physical objects may bedesignated as anticipated targets, because they will likely be rescannedin subsequent LIDAR scans. Additionally or alternatively, anticipatedtargets may be determined based on map data and/or a current location ofthe vehicle or LIDAR device. As such, an appropriate power output levelmay be adjusted based on an anticipated location of the target object.That is, light pulses anticipated to interact with target objects closeto the vehicle may include relatively less power than those light pulsesanticipated to interact with target objects far from the vehicle.

Optional Block 706 includes causing the given light-emitter device toemit at least one light pulse into an environment toward a targetlocation according to the desired power output level.

In some embodiments, method 700 includes determining a region ofinterest in the environment. As an example, determining the desiredpower output level may be further based on determining that the regionof interest corresponds to the target location of the givenlight-emitter device.

In some embodiments, method 700 may include receiving informationindicative of a reference angle. In such scenarios, determining theanticipated target range may be based on the received information. Asdescribed above, the reference angle could relate to, for example, aforward movement direction of the vehicle 300. In such a scenario, morepower may be applied to at least some laser pulses that are emitted at ahigher effective elevation angle (e.g., due to the vehicle going up ahill) at least because the laser pulse may travel a longer anticipatedtarget distance (and be subject to more scattering and otherinterference effects) compared to if the vehicle was traveling along aflat surface. Conversely, in some situations, less power may be appliedto at least some laser pulses, which may be emitted at a lower effectiveelevation angle (e.g., due to the vehicle moving down a hill). In suchscenarios, the laser pulses may travel a shorter anticipated targetdistance before interacting with an object or target, and may thus beeffectively detected using less power than in a flat-surface scenario.

FIG. 8 illustrates a method 800, according to an example embodiment.Method 800 may provide a way to adjust a desired shot schedule of agiven light pulse or pulse train emitted by a given light-emitter devicebased on a respective elevation angle of the light-emitter device.Method 800 may involve elements that are similar or identical to thoseillustrated and described in reference to FIGS. 1A, 1B, 2A, 2B, 2C, 3A,and/or 3B. It will be understood that the method 800 may include feweror more steps or blocks than those expressly disclosed herein.Furthermore, respective steps or blocks of method 800 may be performedin any order and each step or block of method 800 may be performed oneor more times. In some embodiments, method 800 may be combined with oneor more of methods 500, 600, 700, or 900.

Block 802 includes determining an elevation angle for each light-emitterdevice of a plurality of light-emitter devices. In such a scenario,respective light-emitter devices are coupled to respective die attachlocations corresponding to respective angled facets of a plurality ofangled facets disposed along a front edge of at least one substrate. Insome embodiments, determining the elevation angle of the light-emitterdevices may be based on an arrangement of the respective light-emitterdevice on the at least one substrate, as described elsewhere herein.

Block 804 includes determining a desired shot schedule of the givenlight-emitter device based on the determined elevation angle. In someembodiments, the desired shot rate could be increased or decreased froma standard shot rate based on the determined elevation angle. Thedesired shot schedule may indicate 1) which light-emitter of theplurality of light-emitter devices is to be fired; 2) how long thelight-emitter should be fired (e.g., a time duration of a given lightpulse); and/or 3) how long to wait before firing the next light-emitter.In such scenarios, the elevation angle may limit a distance that a givenlight pulse may travel before it interacts with a ground surface or aphysical object. For example, the desired shot schedule may be adjustedto decrease the time to wait after firing a light pulse from adownward-pointing light-emitter device, in cases where, for example, theelevation angle is below the horizontal plane (zero degrees) or below −5degrees from the horizontal. In other scenarios, the desired shotschedule may be adjusted to increase the time to wait after firing alight pulse from an upward-pointing light-emitter device when thedetermined elevation angle is above, for example, −5 degrees or thehorizontal plane (zero degrees).

In some embodiments, determining the desired shot schedule may befurther based on a comparison between the elevation angle and at leastone value in a lookup table. In some instances, the lookup table may bestored in memory 154 and may be updated dynamically based on, forexample, real-time or historic point cloud data.

Optional Block 806 includes causing the plurality of light-emitterdevices to emit light pulses into an environment toward a target regionor region of interest according to the desired shot schedule. Forexample, a pulser circuit may cause laser diodes to emit a light pulseor a plurality of light pulses (e.g., a pulse train) according to thedesired shot schedule (e.g., firing the laser diodes in a given order,with a given pulse duration, and with a given wait time before the nextlight pulse).

In some embodiments, method 800 may include determining a region ofinterest in the environment. In such scenarios, determining the desiredshot rate is further based on determining that the region of interestcorresponds to the target region of the given light-emitter device. Asdescribed elsewhere herein, the region of interest may include, but neednot be limited to, a vehicle, an object, a person or another livingbeing, an obstacle, a traffic sign, a hazard cone, or another type offeature within the environment of the sensor system that may representimportant information relating to the operation of the sensor system orthe vehicle to which it is mounted.

In some embodiments, method 800 may include receiving informationindicative of a reference angle. In such scenarios, determining theelevation angles may be based on the received information.

FIG. 9 illustrates a method 900, according to an example embodiment.Method 900 may provide a way to adjust a desired shot schedule of aplurality of light-emitter devices based on an anticipated target range.As described above, the desired shot schedule may indicate 1) whichlight-emitter of the plurality of light-emitter devices is to be fired;2) how long the light-emitter should be fired (e.g., a time duration ofa given light pulse); and/or 3) how long to wait before firing the nextlight-emitter. Method 900 may involve elements that are similar oridentical to those illustrated and described in reference to FIGS. 1A,1B, 2A, 2B, 2C, 3A, and/or 3B. It will be understood that the method 900may include fewer or more steps or blocks than those expressly disclosedherein. Furthermore, respective steps or blocks of method 900 may beperformed in any order and each step or block of method 900 may beperformed one or more times. In some embodiments, method 900 may becombined with one or more of methods 500, 600, 700, or 800.

Block 902 includes determining an anticipated target range for eachlight-emitter device of a plurality of light-emitter devices. Therespective light-emitter devices are coupled to respective die attachlocations corresponding to respective angled facets of a plurality ofangled facets disposed along a front edge of at least one substrate. Theanticipated target ranges could be based, at least in part, on therespective arrangements of light-emitter devices on the at least onesubstrate. The anticipated target ranges could be additionally oralternatively based on a ground surface. In other embodiments, theanticipated target ranges could be based on historical point cloud dataand/or target object recognition information. That is, the anticipatedtarget ranges may relate to a previously-scanned, and/or specificallyidentified, target object, which could have been scanned by the same oranother LIDAR device at an earlier time.

Block 904 includes determining a desired shot schedule of the pluralityof light-emitter devices based on the respective determined anticipatedtarget ranges. In other words, the desired shot schedule could beadjusted from a standard shot schedule (e.g., raster-scan sequentialemitter firing, standard pulse duration, standard wait time before nextpulse, etc.) based on an anticipated range to a given target or possibletarget. For example, the wait time between pulses may be decreased incases where, for example, the anticipated target is at relatively closerange (e.g., within 5 meters of the front bumper). In other scenarios,the wait time between pulses may be increased when an anticipated targetis at relative long range (e.g., more than 25 meters from the frontbumper).

In some embodiments, determining the desired shot schedule may befurther based on a comparison between the respective anticipated targetranges and at least one value in a lookup table. In some instances, thelookup table may be stored in memory 154 and may be updated dynamicallybased on, for example, real-time or historic point cloud data.

Optional Block 906 includes causing the plurality of light-emitterdevices to emit light pulses into an environment toward a target regionaccording to the desired shot schedule. For example, a pulser circuitmay cause laser diodes to emit a light pulse or a plurality of lightpulses (e.g., a pulse train) according to the desired shot schedule(e.g., firing the laser diodes in a given order, with a given pulseduration, and with a given wait time before the next light pulse).

In some embodiments, method 900 may include determining a region ofinterest in the environment, wherein determining the desired shotschedule is further based on determining that the region of interestcorresponds to the target region of at least one light-emitter device ofthe plurality of light-emitter devices.

The method 900 may include receiving information indicative of areference angle. For example, determining the respective anticipatedtarget ranges may be based on the received information.

The particular arrangements shown in the Figures should not be viewed aslimiting. It should be understood that other embodiments may includemore or less of each element shown in a given Figure. Further, some ofthe illustrated elements may be combined or omitted. Yet further, anillustrative embodiment may include elements that are not illustrated inthe Figures.

A step or block that represents a processing of information cancorrespond to circuitry that can be configured to perform the specificlogical functions of a herein-described method or technique.Alternatively or additionally, a step or block that represents aprocessing of information can correspond to a module, a segment, aphysical computer (e.g., a field programmable gate array (FPGA) orapplication-specific integrated circuit (ASIC)), or a portion of programcode (including related data). The program code can include one or moreinstructions executable by a processor for implementing specific logicalfunctions or actions in the method or technique. The program code and/orrelated data can be stored on any type of computer readable medium suchas a storage device including a disk, hard drive, or other storagemedium.

The computer readable medium can also include non-transitory computerreadable media such as computer-readable media that store data for shortperiods of time like register memory, processor cache, and random accessmemory (RAM). The computer readable media can also includenon-transitory computer readable media that store program code and/ordata for longer periods of time. Thus, the computer readable media mayinclude secondary or persistent long term storage, like read only memory(ROM), optical or magnetic disks, compact-disc read only memory(CD-ROM), for example. The computer readable media can also be any othervolatile or non-volatile storage systems. A computer readable medium canbe considered a computer readable storage medium, for example, or atangible storage device.

While various examples and embodiments have been disclosed, otherexamples and embodiments will be apparent to those skilled in the art.The various disclosed examples and embodiments are for purposes ofillustration and are not intended to be limiting, with the true scopebeing indicated by the following claims.

What is claimed is:
 1. A system comprising: at least one substratecomprising a plurality of angled facets along a front edge, wherein theat least one substrate further comprises a die attach locationcorresponding to each angled facet, wherein the plurality of angledfacets provides a corresponding plurality of elevation angles, wherein aset of angle differences between adjacent elevation angles comprises atleast two different angle difference values; and a plurality oflight-emitter devices, wherein respective light-emitter devices arecoupled to respective die attach locations according to a respectiveelevation angle of the respective angled facet, wherein the plurality oflight-emitter devices is configured to emit light into an environmentalong the plurality of elevation angles toward respective targetlocations.
 2. The system of claim 1, wherein the at least one substrateis disposed along a vertical plane, wherein the plurality of elevationangles are defined with respect to a horizontal plane.
 3. The system ofclaim 2, wherein at least one respective angle difference betweenadjacent elevation angles below the horizontal plane is greater thanrespective angle differences between adjacent elevation angles above thehorizontal plane.
 4. The system of claim 2, comprising six substrates,wherein each substrate comprises a respective plurality of angled facetsthat correspond to a respective portion of the plurality of elevationangles.
 5. The system of claim 4, wherein the six substrates are coupledtogether and aligned according to a set of alignment features, whereinthe plurality of light-emitter devices is distributed between each ofthe substrates, and wherein each portion of the plurality oflight-emitter devices is configured to illuminate the environment at arespective pointing angle with respect to the vertical plane.
 6. Thesystem of claim 1, wherein a spatial resolution is about 7.5 centimetersbetween adjacent target locations along a horizontal ground plane. 7.The system of claim 1, wherein the plurality of light-emitter devicescomprises at least 64 light-emitter devices.
 8. The system of claim 1,wherein the at least one substrate further comprises, for eachlight-emitter device, a respective pulser circuit, wherein eachrespective pulser circuit is configured to accept a power signal, anenable signal, and a trigger signal, wherein the respective pulsercircuits are configured to provide pulses between 1-10 nanoseconds induration.
 9. The system of claim 1, further comprising a plurality oflenses, wherein each respective light-emitter device of the plurality oflight-emitter devices is optically coupled to a respective lens of theplurality of lenses.
 10. The system of claim 1, further comprising avehicle, wherein the plurality of light-emitter devices is configured toemit light into an environment around the vehicle.
 11. A method ofmanufacturing, the method comprising: providing at least one substrate,wherein the at least one substrate comprises a plurality of angledfacets along a front edge and a die attach location corresponding toeach angled facet, wherein the plurality of angled facets provides acorresponding plurality of elevation angles, wherein a set of angledifferences between adjacent elevation angles comprises at least twodifferent angle difference values; attaching a plurality oflight-emitter devices to respective die attach locations, wherein theattaching is performed according to a respective elevation angle of therespective angled facet; electrically connecting each respectivelight-emitter device of the plurality of light-emitter devices to arespective pulser circuit; and optically coupling each respectivelight-emitter device of the plurality of light-emitter devices to arespective lens.
 12. The method of claim 11, wherein attaching theplurality of light-emitting devices is performed with a conductive,thermally-cured adhesive, and wherein electrically connecting eachrespective light-emitter device of the plurality of light-emitterdevices to a respective pulser circuit comprises providing a pluralityof wire bonds between the respective light-emitter device and therespective pulser circuit.
 13. The method of claim 11, wherein opticallycoupling each respective light-emitter device of the plurality oflight-emitter devices to a respective lens comprises aligning therespective lens to the respective light-emitter device through an activeoptical feedback control process.
 14. The method of claim 13, whereinthe active optical feedback control process comprises causing therespective light-emitter device to emit light and adjusting a positionof the respective lens such that a target location is illuminated by theemitted light having a desired light pattern.
 15. A system comprising: aplurality of light-emitter devices of a light detection and rangingsystem of a vehicle, wherein each light-emitter device of the pluralityof light-emitter devices is configured to emit light pulses along arespective beam elevation angle, wherein the plurality of light-emitterdevices are arranged such that a combination of the respective beamelevation angles comprises a non-uniform beam elevation angledistribution, wherein at least one angle difference between respectivebeam elevation angles of two adjacent light-emitter devices havingelevation angles below a reference plane is larger than at least oneangle difference between respective beam elevation angles of twoadjacent light-emitter devices having elevation angles above thereference plane, wherein the reference plane is based on an axis ofmotion of the vehicle.
 16. The system of claim 15 wherein less than 50%of the plurality of light-emitter devices have respective beam elevationangles below the reference plane.
 17. The system of claim 15 wherein atleast one light-emitter device with a respective elevation angle belowthe reference plane is configured to emit light pulses at a higher shotrate than at least one light-emitter device with a respective elevationangle above the reference plane.
 18. The system of claim 15 wherein atleast one light-emitter device with a respective elevation angle abovethe reference plane is configured to emit light pulses with a lower dutycycle than at least one light-emitter device with a respective elevationangle below the reference plane.
 19. The system of claim 15 wherein atleast one light-emitter device with a respective elevation angle belowthe reference plane is configured to emit light pulses with a lower dutycycle than at least one light-emitter device with a respective elevationangle above the reference plane.
 20. The system of claim 15 wherein atleast one light-emitter device with a respective elevation angle belowthe reference plane is configured to emit light pulses with a lowerpower output per pulse than at least one light-emitter device with arespective elevation angle above the reference plane.